Method of treating pistons



H. M. OLSON METHOD OF TREATING PISTONS March 7, 1939.

Filed Aug. 16, 1937 2 Sheets-Sheet 1 Mm 7,1939. H OLSO 2,149,787-

METHOD OF TREATING PISTONS Filed Aug. 16, 1937 2 Sheets-Sheet 2 I Alkm eg Patented Mar. 7, 1939 PATENT OFFICE 2,149,737 METHOD OF mm'rmc PISTONS Holly M. Olson, Muskegon, Mich., assignor to Sealed Power Corporation, Muskegon, -Mich., a

corporation of Michigan Application August 16, 1937, Serial No. 159,313

6 Claims.

This invention relates to piston expanding, and is concerned with a novel method and apparatus for expanding particularly the skirts of worn pistons after said pistons have had service in engines, to enlarge the piston to better fit the cylinder in which it operates. With my invention a machine is provided wherein a piston may be positioned and fixed in the machine, the machine operated and the piston will be acted against at its inner sides and at diametrically opposite points by pointed impact rods, the force of the impact of the rods against the inner sides of the piston serving to displace the metal and in effect stretch the piston around its outer surface so as to enlarge the same. The piston also may be turned about its vertical axis while this operation is being performed to increase the area or surface over which the operation is performed at the inner sides of the piston, thereby producing a more perfect operation.

An understanding of the invention may be had from the following description, taken in connection with the accompanying drawings, in which, Fig. 1 is a side elevation of a machine embodying my invention.

Fig. 2 is a front elevation thereof without the flywheel.

Fig. 3 is a plan View.

Fig.4 is a fragmentary enlarged vertical section through a piston which is being operated upon by the machine.

Fig. 5 is a horizontal section through the piston shown in Fig. 4, and the adjacent parts of the machine on which it is mounted.

Fig. 6 is an end elevation of the element of the machine in which the impact rods are mounted,

Fig. 7 is a central vertical section therethrough, and

Fig. Sis a horizontal section of a modified form I of impact rod holder and mounting element therefor.

Like reference characters refer to like parts in the different figures of the drawings.

The support of the machine comprises a horizontal member I shown as of angle iron form which is permanently secured to any suitable supporting base 2, and at one end of which a vertical post 3 of similar angle formation extends upwardly as shown. On one leg or flange of the post 3 and between its ends a bearing 4 is secured in which a horizontal shaft5 is rotatably mounted, which shaft is provided with a wheel Ii to be driven by any suitable belt from a line or power shaft. It is to be understood that the shaft 5 may be driven in any other suitable manner. At the other end of the shaft a circular disk I is secured from which a pin 8 extends located off-center of the disk.

A second bearing 9 is bolted or otherwise s- 5 cured to the same side of the post 3 at its upper end. A rock shaft It] extends through said bearing and is equipped with a head I I directly above the disk I to the face of which a flat bar I2 is permanently secured. The bar I2 extends down- 10 ward and at its lower end is slotted vertically, as at I3, for a distance receiving a slide block I4 through which the pin 8 on the disk I extends.

It is evident with this construction that on rotation of the shaft 5 the bar I2 is oscillated back and forth about the axis of the rock shaft I 0, the throw of the lower end of the bar I2 being equal to twice the distance that the axis of pin 8 is spaced from the axis of the shaft 5.

A bracket [5 is attached to the bar I2 a short distance below its upper end and extends horizontally outward. A guide I6 is adjustably secured to a plate I1 fixed to the outer side of the bar l2. Through the bracket I5 and the guide I 6 a rod I9 passes. It is equipped at its upper end with a horizontally extending handle 20. At the lower end of the rod I9 below the guide I6 a horizontal fiat plate or bar 2| is permanently secured having metal clips 22, one at each end, which extend inwardly-toward each other underneath the outer end portions of the bar 2!. The shanks of screws 23 pass through the bar 2I and thread through suitable openings in the clips 22. The free ends of the clips 22 are adapted to enter the upper ring groove in a piston 24 located with its upper end immediately below the bar 2I, and by turning the screws 23 in the proper direction the clips are drawn upwardly to clamp the upper end of the piston to the bar.

The lower end of the piston rests upon a second 4 bracket which has a horizontal outwardly extending table 25, such bracket and table being carried on the bar I2 and extending outwardly therefrom below but in the same direction as the bracket I5. The lower end of the piston is located between two L-shaped brackets 26 which may be adjustably mounted on the table 25 and brought with their vertical legs at opposite sides of the piston. With this installation the piston moves back and forth with the oscillation of the bar I2.

A block 21 having oppositely extending ears 28 at its lower side is located above and secured to the table 25, suitable fastening means passing through said table and threading into the ears 28. Said block is located so that when the piston is placed thereover the opposite ends of the block are spaced from opposite inner sides of the piston substantially equal distances. The block is provided with longitudinal horizontal guide openings therein in which rods 29 are mounted for In operation with this construction and rotating the shaft 5 at a suitable speed, the back and. forth movement of the lower end portion of the bar I2 and of the piston 26 causes the pointed rods 29 to be reciprocated back and forth in the guide openings in the block 2'! whereby the ends of the rods are impacted against diametrically opposed inner sides of the piston. The handle 20 may be manually operated to turn the piston through an arc so as to increase the area of impact of the rods against the inner surface of the piston, the impact and impingement of the outwardly pointed ends of the rod against the opposite inner sides of the piston is equal at both ends of the rods thereby getting a symmetrical enlargement of the piston skirt. The piston, usually of aluminum or an aluminum alloy, is indented by the pointed rods which are usually of steel, the points being hardened, with a resultant increase 'of circumference of the piston. In practice this increase or enlargement of circumference may be only a few thousandths of an inch but that is sufficient for enlarging the piston to correspond with the cylinder in which it has been operating and in which the wear upon both the cylinder and piston has made the fit of the piston within the cylinder too loose.

This method of enlarging pistons is one by means of which the operation is easily performed and produces a substantially perfect product. It is of course to be understood that the block 2'! does not necessarily have to carry the impact rods in the number and location such as shown in Fig. 6, but such arrangement of the rods in the block may be varied in many respects. This increase in circumference or stretching of the piston skirt has come to be an accepted way of repairing engines with respect to worn pistons in worn cylinders and the method which I have invented produces the enlarged piston skirt result in a very rapid, practical and efficient manner.

In Fig. 8 the block 21a does not have the passages for the rods 29 extend entirely through the block, but such passages are closed at one end as shown. The outer pointed ends 30 of the rods strike against the inner side of the skirt of the piston 24', and there does not occur an action upon the inner side of the piston at diametrically opposed points as with the structure shown in Fig. 7. With this modified form of rod carrying block, any selected part of the inner side of thepiston skirt may be operated upon without at thev same time performing the same operation upon a portion of the piston ring skirt diametrically opposite. The pins 29 are reciprocated in the same way and that part of the inner side of the skirt where the pointed ends strike is indented and the action upon the piston is the same at the points of striking. The present invention is not to be limited to the operation of the rods at both ends against opposite inner sides of the piston, but is to comprehend the method and apparatus for acting against the inner side of the piston at any selected portion thereof. The ends at 30 of the impact rods likewise may be of different shapes. The point does not need to be sharp but can be blunted or a ball point located either in line with the axis of the rod or to one side thereof. All of such minor variations are to be considered comprehended by my invention.

Having thus fully described my invention what I desire to claim and secure by Letters Patent is:

1. The method of treating pistons which consists in impacting loosely mounted pointed rods against the inner surface of the piston by oscillating said rods and said piston.

2. The method of piston treatment which consists, in locating a piston over a member having guide passages in which pointed rods are loosely mounted, and in bodily oscillating the piston and said member in a direction substantially parallel to a diameter of the piston, whereby said rods are reciprocated and strike at their pointed ends against portions of the inner side of the piston.

3. The method of piston treatment which consists, in positioning loosely mounted rods within a piston and reciprocating said rods and piston, said rods being of less length than the diameter of the piston whereby the ends of the rods strike the inner sides of the piston.

4. The method of piston treatment which consists, in locating a piston over a member having guide passages in which rods are loosely mounted, and in oscillating said member and piston, whereby said rods are reciprocated and strike against the inner side of the piston.

5. The method of piston treatment which consists in the steps of locating within a piston loosely mounted rods, oscillating said rods and said piston, and rotating said piston about its own axis during the oscillatory motions.

6. The method of piston treatment which includes the steps of securing a member having loosely mounted rods therein to a plate, securing a piston in position on said plate and around said member, and oscillating said plate whereby the ends of the rods will strike the inner sides of the piston.

HOLLY M. OLSON. 

